The present invention relates to a data transmission system. More particularly, the present invention relates to a data transmission system in which data signals from a plurality of data sources within a borehole may be transmitted to the surface by means of a single cable which may be a power cable.
The present invention is particularly useful in the art of drilling boreholes for oil wells and oil well exploration. However, the present invention may be extremely useful in any other type of drilling operation or in any other area where similar requirements are placed on the communication system. During the drilling of boreholes in the earth, such as for oil well exploration, it is highly desirable that information from a plurality of sensing devices be sent to the surface on a real-time basis. This is especially important in making the drilling operation efficient. The present invention enables the information from the borehole to be instantaneously transmitted to the surface. In addition, the present invention enables information from a large number of data sources to be sent to the surface on a real-time basis. The sending of this information from a plurality of data sources or monitoring instruments enables adjustments to be made in the drilling operation instantaneously, such as a change in the direction of the drilling of the borehole.
Typical systems in the past used photographic devices to make photographic recordings of instrument readings in the well borehole. Such prior systems of obtaining instrument readings on the surface proved to be highly inefficient since they required the retrieval of the photographic equipment and a delay in developing the film before the information was available on the surface to make a decision with respect to adjustments in the drilling operation. The present invention overcomes these problems and provides real time information to the surface from a plurality of data sources.